U.S. Representative Beto O'Rourke (D-TX) campaigns in Dallas, Texas, on September 14, 2018. - O'Rourke is the Democratic challenger for the U.S. Senate seat currently held by U.S. Senator Ted Cruz (R-TX) (LAURA BUCKMAN/AFP/Getty Images)

Senator Ted Cruz (R-TX) rallies for a change in the renewable fuel standard during a visit of the bankrupt refinery of Philadelphia Energy Solutions, in South Philadelphia, PA, on February 21, 2018. (Photo by Bastiaan Slabbers/NurPhoto via Getty Images)

American country musician Willie Nelson, in formal attire, performs during a Valentine's Day concert at the Beacon Theater, New York, New York, February 14, 1995. (Photo by Jack Vartoogian/Getty Images)

HORSESHOE BAY, TX - AUGUST 16: U.S. Rep Beto O'Rourke (D-TX) of El Paso speaks during a town hall meeting at the Quail Point Lodge on August 16, 2018 in Horseshoe Bay, Texas. ORourke will be challenging incumbent Sen. Ted Cruz (R-TX) for the senate seat in the November elections. (Photo by Chris Covatta/Getty Images)